Apparatus for regulating the composition of mixed gases



1,682,6891 l c. Hf sMofJ-rl APPARATUS Fn REGULATIPLG THE 4cQnvPosI'1IcmoF urxnn oas-ss -Fileq Feb. 2,"1927 3' Sheets-Sheet 1 .za v i1 27 IN TOR 5W Aug. 2s, 192s.

AITORNEYS Aug. 28, 1928.

\ c. H. sMooT APPARATUS Fon REGULATING THE COMPOSITION oF MIXED GASES Filed Feb. 192'.'

3 Sheets-Sheet 2 HIIiIiMIHWXHH YAug'. 28, 1928. l

'Y y H. SMOOT l APPARATUS Fon REGULATING THE COMPOSITION oF MIXED eAsns ooi-L Patented Aug. 28, l19'28".

Y UNITED ,y STATES CHARLES n. snoer, on narnnvvoon, NEW-JERSEY.

Y APPARATUS FOR REGULATIEN'G UOHIP-DSITIQN OF MIXED GASES.

Application sied February a, 1927. serial n. 165,397. f

My invention relates to the regulation of theconstituents of a mixed gas and comprises novelapparatus adapted to effect such regulation, which Vapparatus 'is automatic in action and sensitive in operation, yet strong,A

rugged and durable under practical service conditions. y'

l By means of my invention many usual sources of error in whatare lknown as gas density regulators or recorders are eliminated and the necessity for delicate auxiliary apparatus for maintaining constant the volurne, temperature or other 'variable condition of the gas is avoided without loss'ot accuracy or sensitivity. Y

My apparatus may be used in the regulation of the composition of any 'mixed gas to control one constituent thereof in response to changes in density caused by changes in the mixture, It is for example well suited to the regulation of the CO2 content of urnace gas-where it may be used to control the ratio of air feed to fuel feed in response to variations in the C()2 content ofthe furnace or flue gas. The particular application of my apparatus is immaterial, however, as my present invention is not concerned therewith.

My invention involves the production and utilization for the regulation of two pressures, one of whichis created by so acting mechanically upon a iiow of the gas to be regulated and the other by simultaneously and identically so acting upon the flow of another gas of unchanging compositionl that the pressures developed at predetermined points in the two flows are equal with a given composition of the gas to be regulated, and becomeuneq'ual only when the composi- -tion of the gas to be regulated varies. Such yinequality of pressures is employed to vary the proportion of the constituents of the gas to be regulated.

The principles upon which my apparatus operates will be made clear by the followingvv Y discussion: Variations in density of samples of mixed gas, the temperatures and volumes of which are equal, indicate differences in the proportions of the various constituents of the gas. A centriiugal fan operating upon a constant quantity of gas and running at constant speed creates a pressure at any point proportional to the square of the radial dis tance from the axis of the fan to that point and to the density of the gas, Under 'con trolled conditions, therefore, by introducing thc inixcd gas into a centrifugal ian, the variations in the density of the gas will cause variations in pressure lat a selected 'point and these variations in pressure may be utilized to operate a regulator to maintain constamt the proportion oi.` the dierent con,

st" r"uents'ei the gas. By utilizing a specially constructed centrifugalian having a practically flat pressure volumeeharacteristic for very small volumes' and by permitting only such small volume of gas to enter the fan as will be within the range of the flat part ofthis characteristic curve, the necessity for maintaining the gas volume strictlyy constant is eliminated. I obviate as well the regulation of the fan speed and the temperature of thegas, by balancing the pressure, the variations in which are to affect the regulation of the gas content against another pressure which is not constant but which varies with the fan speed and gas temperature in the same way as does the controlling pressure. This is accomplished by operating two similar fans-on-the shaft of a single motor, which insures equality of speed, by circulatin .water or other liquid continuously througinterconnected casings of the two fans which insures equality of temperature, and by operatingthe second fan upon a small 'volume of air or other constant density gas and utilizing the pressure of` the air at some definite radial distance from the axis of this second fan to'balance the gas pressure generated by the first fan at a definite radial distance from its axis. Variations between these two pressures are `then used to control the gas content in any desired manner.

For a better understanding of my inventionV and for the advantages pertaining thereto, reference should be had to the accompanying drawings of which Fig. 1 is a vertical section of the preferred form of my apparatus,

Fig. 2 is'a side view thereof partly in section, and `i Fig. 3 isa diagrammatic representation of an application of-my invention tothe control of the CO,v content of the furnace gases. v

Referring to Figs. l and`2 in which llike numerals represent like parts, similar fans l and 2 mounted. on the shaft 3 of motor 4 receive gas and air respectively lthrough two chamber formed by the casing 9 and a exhaust directly to atmosphere at 7 and ra dial' blades 8 in the casings 9, permitting radial but not circumferential flow of the air or gas'before exit from the casing, insure substantially atmospheric pressure at the peripheries of the fans. The fans 1 and 2 are built onvthe 'general principles disclosed in my patent No. 1,361,107, Agranted December .7, 1920, but modified somewhat. A

. imilarly a chamber formed by the casing 9 and disk 16 communicates through passage 17 with the air space of fan 2 and With the device 13 through pipe 18.

The disks 11 and 16 are mounted on shafts 19 and y20 Vrespectively which, passing Vthrough bushings, extend through the casings 9 and are free to turn therein. The shafts 19 and 20 are parallel to, but slightly out of line with, the shaft 3 upon which the fans are mounted, as a result of which a ro- A tation of the disk 11 or 16 changes the radial distance from the axis of the fan to the passage 12 or 17. To the shaft 19-is fastened i one end of a lever arm 21, tlieother end of which is free to be moved by hand over a dial 22; a relatively large angular movement of the arm 21 resulting in a-relativel'y small radial displacement of the passage 12 with respect .to the axis of the fan 1. The casings 9 are double walled and interconnected as indicated by the dashed lines in Fig. 1 and `serve as a jacket through which water is continuously circulated. This insures that both -fans are at the same temperature. Any suitable openings in the casings 9 may Y be made for the introduction and withdrawal ofthe circulating water.

. by-means of pipe 14. The space above the `float is in communication with chamber 1 5 by means of pipe 18. As shown, the cylindrical rfloat 24 .has a central hollow cylindrical portion26 of relatively small diameter extending vinto the liquid considerably below Vthe float proper and having an end closure 27. Passages 28 permit liquid to enter the interior of the cylinder 26. A tube 29 supported by the upper wall of the chamber 23,.

, through which it passes, extends into the cylend to the atmosphere b as f inder 26 and terminates just above the elo: sure 27. The upper end of the tube 29 1S open to the atmosphere. A A tube 30, passing through the tube 29, is attached at one end to the closure 27 and at the other end to a lever mechanism 31 and serves to transmit vertical motion of the float 24 to the lever 31. The interior of tube 30 is opened at the lower end to the liquid and at the upper respectivel v TTI) 1e space 4enclosed by the float 24 is a partially submerged open vessel 34 which is carried by the cylindricalv portion 26 and which has a leakage port 36 in its base. A

resilientmember 35 is interposed between the port 36 and a screw 37, which screw is threaded into a lug 38 carried by the cylinder 26. The leakage permitted through port 36 may thus be varied bythe screw 37. Then the float moves in either direction a temporary difference in the level of the liquid within and .without the vessel 34 occurs which, while present, offersopposi'tion to the further movement of the ioat. The duration of this difference in liquid level depends upon the leakage through port 36 permitted by screw 37.

The lever 31 rests on a knife edge shown indotted lines at 39. Supported by the `lever 31 and hanging therefrom by a knife edge 40 is.a member 41 terminating in a conical tip 42. The tip 42 serves as a leakage valve for a chamber 44 by artially closing a port 43 in the wall thereo the degree of leakage permitted from chamber 44 thus dependingy upon the position of the lever 31. A weight 45, preferably capable of both horizontal and vertical adjustment, serves asa counter balance to the -forces due to the weights of member 4l and float 24 acting on the lever 31.- Any displacement of the lever 31 from its neutral position may be observed by means of aA vertical scale 46 located just behind one end of the lever.

Located ,below the motor 4 and fans 1 andy 2 are saturators 47 and 48 through which the gas and air must pass before reaching pipes 5 leading to the fans. Due to the saturation of boththe air and gas whenpassing through the saturators, any variations 1n moisture content of the atmosphere will not affect the accuracy of the apparatus: Manually adjustable throttling valves 49 1n pipes 5 as well as the small size' of the inlets 6 insure that the volume of gas or air admitted to the fans is very small relative to the capacity of the fans. In theparticular embodiment of my invention illustrated 1n the drawings, the saturators 47 and 48 are each provided with two inlet pipes, onel at the front and one at the rear of each v how many different samples of gas are needed to insure that the density of the gas received by the fan is the average of that of the gas as a whole.

` In o eration the pipes 52 are open to the ,atmosp ere and the pipes 50 are connected to the gas, the composition of which is to be regulated. The lever 21 is set to that part y of the scale 22 representing the desired composition, the motor 4 is started as by switch 54 and the circulation of water through the casings 9 is begun. In the particular case illustrated the regulation is to be effected by a motive iiuid, variations in the pressure Aof which are to be caused by variations in the leakage through port 43 of chamber 44. The pipe 56, therefore, leads to both a source of motive fluid and an element to be regulated, such as a pressure operated damper in the path of flow of one constituent of the gas. The exact manner, however, in Which the variations in pressure within' the chamber 44 are made to vary the gaseous density is immaterial -to my present invention. The

suction of the'large capacity fan 1 draws the gas whose composition' is to be regulated, through the pi pes'50 and water soaked strip 51, where it becomes thoroughly saturated with moisture, into the pipes 5 and through the constricted inlets 6 to the fan chamber. The pressure of the gas at ent-rance to this chamber is negative and will vary withV the density. Upon entrance to the chamber the speed of the fan causes the gas to till the entire space around the fan and to exert pressures increasing with the square of the radial distance from theaxis of the Vfan to the periphery where the pressure is `that i of the atmosphere. The static pressure in the chamber 10 is the same as that at the laverage radial distance of the passage 12 from the axis of the fan 1, and this pressure is transmitted through the gas in pipe 14 to the space enclosed between the float and the liquid in the chamber 23. Similarly air is drawn by the fan 2 through the pipe 52, strip 53, pipes 5 and inlets 6 into the fan chamber, tand the pressure at the average .radial distance from the axis of this fan to the passage `1'? is transmitted to the space abovethe float in chamber 23. If thedensity of the gas is that desired, and for which the lever arm 21 has been set, the pressures acting uponthe float` 24 will be equal and the same amounts. lf, however, the composition of the gas Varies so as to increase the density, there will be a greater difference in pressure between the axis of the fan 1 and the periphery inasmuch as the pressure difference varies with the density. As the pressure at the periphery is maintained atmospheric it follows that the absolute value of the pressure 4in the chamber 10 must decrease with increase in 'density' of the gas. This decrease in pressure results in 'a downward movement of the oat 24 and tube 30, in a rocking of the lever 31 and av conscquent decrease in leakage from the chamber 44. Assuming now that the apparatus is regulating the CO2 content of a furnace, the decrease in leakage from chamber 44 will increase the pressure onsome auxiliary regulator and cause it to increase the amount of air supplied to the furnace n proportion to the amount of fuel fed thereto to thus reduce the C()2 content and therefore the' i density of the furnace gas. lVhen the composition of the gas has been returned to the desired value the pressures acting on the float will again be equal. Similarly a decrease in density of the gas causes the pressure beneath the float to increase and results in an upward movement of the float and a greater leakage from the chamber 44 until the density has been returned tothe desired value. i

When it is desired to regulate to some other value of the densityit is only necessary to move the arm 21 to another position on the scale 22 corresponding with, the density now desired. When using the appara tus to control combustion the division on gicle) scale 22 could representv percentages of 2' 'The distancebetween the axis ofthe air far. remains unchanged during the operation of the device, although itv is 'possible to vary this latter distance by turning the shaft 20. 'This' is, however, merelya matter of convenience in vfactory the opening 17 andadjustment and is not essential-to the opl boiler furnace is shown Avdiagrammatically in Fig. 3 in which vthe regulator is shownat 57 With the pipes 50 leading into a boiler furnace 58 and terminating in the pathofl l' -flow of the gases of combustion, and with the pipe 56 leading to a balance device 59 .controlling the position of a damper 60 in the air su ply line 61. A source oflpressure, not s own, is connected by means of pipe 63 `with pipe 56 and pipe 62 leads from a point in the conduit 61 beyond the damper 60 to thedevice 59. The device 59 may be any well known type of pressure balance and may control the damper mechanically or through an auxiliary source of motive Within' fthe chambers 66 and 67 exerting forces u on the diaphragms 68 and 69 respective y, which diaphragms are connect-V ed to the ends of the lever 64I by meansof rods/70 attached thereto. The pipe 62 connects with the chamber 66 and the pipe 56 with chamber 67.

With the arrangement shown in Fig. 3,

` when the C()2 content of the furnace gas increases, v the density of the gas drawnV through pipes increases, resulting m a decrease in the leakage permitted from pipe 56 as explained in connection with Figs. 1. and 2. The pressure Within the chamber67 thereby increases sufiiciently to move the lever 64 in aclock-Wise direction, thus pulling on rod 71 which, through bell crank lever 72, rod 73 and arm. 74, moves the damper into a more open position. The

opening of the damper lpermits more air to enter 'the furnace thus reducing the CO2 content of the gases. in CO2 content results in a Vpartial closure of the damper to return the lever 31 Fig.

1) to neutral position by the return o the CO2 content to the value corresponding to the setting of the arm 21 on the scale 22. The pressure transmitted through pipe 63 may be constant, manually adjusted or automatically controlled in accordance WLith the steam pressure as desired. The device 59 operates to maintain the pressure of the air supplied to the furnace proportional to the-pressure Within the chamber 67. lfVhen using this apparatus with a system of centralized regulation, such as is described and claimed in my Reissue Patent No. 16,507, granted December 21, 1926, the 'pipe 63 would Vlead from a master controller and wouldtransmit master air pressure, adjusted by the gas density regulator to the dia# phragm 69, in which case also the stoker (not shown) would be controlled directly from the master controller independently of .the device 57.

I have now described and illustrated my invention in the form preferred by me. Ob viously many substitutions or omissions of parts could be made without departing from the spiritv4 of my invention. Any suitable jected lto such type ofsensitivo pressurey balance could be used instead of the device 13, although'I prefer the balance device described as it is Well suited to accurately regulate when subressures as' are produced by the apparatus escribed. It is of course immaterial whether the lever mechanism controls a leakage port, as shown, orany other regulating device, as, for .example, an elecltrical resistance. My apparatus 1s essentially'a regulator and not an indicator of gaseous. density. Whenever Vit is' desired,

Conversely a decreasehowever, to use the a paratus as a meter it is only necessary to etermine by trial the position on the scale 22 of the arm 21 which corresponds with the neutral position of the lever 31, this position of the arm 21 then indicates the gaseous density on the scale 22.

Haiving thus described 'my invention, what I claim, and desire to protect by Letters Patent is:

1. In a regulator for'controlling the composition 'of mixed gases, means for producing under like conditions two varying pressures, one affected by the density of the gas Whose composition is to -be regulated, and one unaffected by such density, and means responsive to both of such pressures for regulating the composition of the gas -to maintain a definite relation between said pressures.

-2..A regulator for controlling the composition of mixed gases, including a fan for creating a pressure, which varies With the density of the gas Whose composition is to be controlled', a second fan for creating a pressure independent of said density, means 'for maintaining the ratio between said pressures independent of the temperature or speed of said fans and means controlled by the differential of said pressures.

3. A regulator for controlling the composition of mixed gases, including a fanfor creating at a definite radial distance from its axis a pressure varying With the density of of said density and means for adjusting one'` of said radial distances. f

4. A regulator for controlling the composition of mixed gases including a centri i'ugal fan rotating in an atmosphere of the gas Whose composition is to be regulated, a second centrifugal fan rotating inan. atmosphere ot' a gas whose composition is constant, means for driving botli of said -fans at the same speed, means for maintaining constant the pressure at the peripheries of said fans and means for balancing the pressure at a definite radial distance from the axis of one f'an against that at a 'definite radial distance from the axis of the second f'an.

5. Apparatus as in claim 4 including means for' adjusting the radial distance from the axis of one of the said fans.

6. Apparatus asin claim 4 including means for maintaining both of said fans at the same temperature. 4

7. A regulator for controlling the composition of mixed gases including a centrifugal fan operating upon the gas whose composition is to b e regulated and cxhausting said gas directly into the atmosphere, a second fan constructed similarly to the first fan and operating upon a gas of constant las composition and also exhausting directly into the atmosphere, means for introducing into said fans the gases to be operated upon in only such amounts as to be, small compared with the capacity of said fans,'a motor drivy ing said fans at the same speed, and means for'balancing the pressures generated by4 `said'fans at definite radial -distances from their axes. i

S. A 'regulator for controlling ythe 4com- Y position of mixed gasesincluding two fans and a motor for-driving the same, two double-walled interconnected casings providingr enclosed chambers for said fans, a

second and smaller chamber within. each of said casings adjacent to the fan chamber and separated therefrom by a disk having a4 i, passage therethrough, said disk being par allel to but eccentric'with said'fans and be ing mounted on a shaft which passes through the walls of the casing, a niovably adjustposition of mixed gases including twofans and a motor4 for driving the same, doublewalled interconnected casmgs for said fans.

permitting a lcirculation of liquid therethrough, restricted inlets through `each 'of said casings, an enclosed chamber-partially filled with liquid, an inverted oat member partially submerged in'said liquid and dividing the space labove the liquid vinto two Y portions, a pipe joinin the .space above'said member With the interior of one of said casings at a definite radial distance .from the axis of theenclosed fan, .a second `pipe con` necting the space conned by the float member with the interiorv of the other of said casings ata definite radial distance from the axis of the other fan, and 'a lever mechanism. connected to said float member and a leakage valve controlled by lsaid leven l 10. A regulator for controlling thecomposition of mixed-gases including .two satu-.

rators, one forthegas whose composition is to be regulated, and one for air,y two fans driven at the sainel speed and enclosed in casings, pipe connections between one of said saturators and vthe-fan chamber within onev 'of said casings, pipe connections between the other one of said saturators and the fan chamber of the other one o f said casings, a restriction in each of said pipes, means for exhausting said fans at atmospheric pressure,and means for balancing the gas pressure at a definite radial distance from the axis of one fan against the air pressure at a deiinite radial distance from the axis of the other fan.

11. In a regulator for controlling thecomposition of mixed gases, means for producing two varying pressures, one aected by :the densityof the `gas whose composition-is to be regulated and one unaffected by such density, pressure responsive means including an inverted float member'partially sub;

merged in liquidmovable by the: difieren@ tial of said pressures and having a central cylindrical Aportion extending' into the liquid substantially below .the main, part of said float, and-means foroffering temporary opposition to the movement of said' float :com rising a partially submerged vessel carried .by said cylindrical portion and i provided with an adjustable leakage port -beneath the surface of the contained liquid.:4

y12. In apparatus responsive to variations in the composition of mixed gases, a movable member, 'means for producing under like con` ditions two varying pressures', one aiiected bv. the density of the mixed gases, and one u'naii'ected'by such density, and means .re-

sponsive tol both of such pressures for con trolling4 said movable member 'to maintain a` definite relation between said pressures.

13. In a regulator for controlling a com- .position of mixed gases means forl producing two varying pressures, one aiiected -by the densityA of the gas whose compositionA is `to be regulated and. one unaffected by such density, pressure responsive means acting to .l

lregulate the' density of the .gas being controlled, said pressure responsive means being subjected to the two varying pressures first mentioned and resilient means for checking the motion of the pressure responsive devlce.

14. In a regulator for controlling a com position of mixed gases means for producing two varying pressures, one affected by the density of-tlie gas whose composition is to be regulated and one unaii'ected by such density, pressure responsive means acting to regulate the densityof the gas'bein'gcontrolled, said pressure responsive means being subjected to the two varying pressures first mentioned, resilient vmeans for' checking the motion of the .pressure responsive device and `means for removing after a lapse of time the eii'ect of thel checking means above.

[In testimony whereof, I have signed my name to this specification.

'CHARLES sMooir. f 

